1. Technical Field
The present disclosure relates to a control apparatus for a hybrid vehicle including an engine and a plurality of motors as driving force sources and, more particularly, to a control apparatus for a hybrid vehicle that is able to travel by using the power of the motors only and that is able to start the engine with the use of any one of the motors.
2. Description of Related Art
An example of a hybrid vehicle that is able to travel by using a motor is described in Japanese Patent Application Publication No. 2003-041966 (JP 2003-041966 A). The hybrid vehicle includes an engine that is cranked by a motor serving as a starter and a motor for propelling the hybrid vehicle as driving force sources. In a hybrid vehicle of this type, when the hybrid vehicle is performing so-called motor driving, the motor for propelling the hybrid vehicle may lock. A control apparatus for the hybrid vehicle described in JP 2003-041966 A is configured to, when it is determined that the motor locks after a lapse of a starting time of the engine and the torque of the motor needs to be restricted, immediately start the engine. Therefore, in the control apparatus described in JP 2003-041966 A, a start of the engine has already completed at the time when torque is restricted due to locking of the motor, with the result that it is possible to prevent a decrease in the driving torque of the vehicle at the time of starting the engine.
Japanese Patent Application Publication No. 2009-298373 (JP 2009-298373 A) describes a hybrid vehicle configured to restrict load factors (the ratios of output driving force to the maximum driving force) of motors on the basis of the temperatures of inverters that respectively control the motors. Control described in JP 2009-298373 A is such that, when it is determined that the inverter temperatures rise due to an abnormality in a cooling system of the hybrid vehicle, the load factors are restricted and the motor for engine rotation speed control and the motor for propelling the hybrid vehicle are controlled within the corresponding restricted load factors. Therefore, it is possible to avoid or reduce a situation, such as an excessively high inverter temperature.